gopher -> gopher://magical.fish, gopher://sdf.org...
gemini -> gemini://gemi.dev, it has geminipedia, a web to gemini converter reading sites over gemini at great speeds.
irc -> servers from https://bitlbee.org will allow upon connecting to a registered IRC account to several protocols in the server. For instance, XMPP users will appear as IRC users and groupchat can be created as IRC channels. Ditto with Mastodon, Discord...
mail/usenet -> well, except for big attachments and news binaries (free NNTP servers will just serve text) once you used something like mbsync/msmtp to store your IMAP mail locally and send email ondemand (and ditto with Usenet with slrnpull doing the same exact same task for pushing your writtings and pulling down new articles) everything would just work slower, but usable enough as it can be just batch-uploaded/downloaded overnight.
Iodine it's really great for open but paid wifi services behind portals, such as some hotels, airports...
It won't give you broadband speeds but you can at least chat with people, read some blogs or news at https://lite.cnn.com or https://text.npr.org or get some classic from Gutenberg. That's better than nothing.
